This invention relates in general to a container for and a method of preserving produce in a wholesome condition for an extended period of time.
A large variety of fruits and vegetables are characterized by relatively short shelf lives in the ripened condition. All fresh produce respires after harvest. The largest gas component of this respiration is carbon dioxide. Significant ethylene is also generated which has a catalytic effect on accelerating ripening rate. It is known that shelf life of perishable produce can be lengthened by preserving them in inert gas filled containers. Oxygen, the all-important life giving element, possesses such unfortunate properties as supporting the growth of bacteria which cause food deterioration and discoloration. Improvement in produce shelf life can be gained by reducing oxygen available for conversion to carbon dioxide, reducing ethylene levels to slow catalytic effects, and maintaining a higher than atmosphere level of carbon dioxide to reduce bacteriological growth. Also, the replacement of oxygen by an inert atmosphere, such as nitrogen, argon or helium inhibits bacterial growth, assuring longer shelf life and retention of flavor and color.
Modified atmosphere containers of the type indicated have been mostly in the form of storage rooms and portable container vans having systems for continuously monitoring and changing the atmosphere to reduce or eliminate oxygen or other gases which affect ripening of produce.
Individual modified atmosphere containers have been tried wherein a sealed container occupied by produce is formed by a high barrier film and filled with a mixture of nitrogen and/or carbon dioxide. One difficulty experienced with such a container is that produce respiration and bacterial action causes gases and volatiles to build up inside the container, resulting in a continuing increase in pressure which eventually produces bulging and even rupture of the container.